Thank you very much for your advice on good PD programming practice. The finished "good programming PD practice" is at:
www.earcatching.com/pdconv
This is intended to apply to situations where PD patches are being shared between users. I don't intend to tell you how you should be doing your personal PD programming! Specifically it is for a project in which 4 of us will be working on the same potentially large-scale patch.
It is a partly a summary of advice received, but mostly a dollup of my own reasoning and personal preferences. Feedback is welcomed. I will update it with necessary changes and note any equally valid alternatives.
Cheers,
Trevor